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Remote Procedure Call
In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure ( subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal (local) procedure call, without the programmer explicitly coding the details for the remote interaction. That is, the programmer writes essentially the same code whether the subroutine is local to the executing program, or remote. This is a form of client–server interaction (caller is client, executor is server), typically implemented via a request–response message-passing system. In the object-oriented programming paradigm, RPCs are represented by remote method invocation (RMI). The RPC model implies a level of location transparency, namely that calling procedures are largely the same whether they are local or remote, but usually, they are not identical, so local calls can be distinguished from remote calls. Remote calls are usually or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Computing
A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer science that studies distributed systems. The components of a distributed system interact with one another in order to achieve a common goal. Three significant challenges of distributed systems are: maintaining concurrency of components, overcoming the lack of a global clock, and managing the independent failure of components. When a component of one system fails, the entire system does not fail. Examples of distributed systems vary from SOA-based systems to massively multiplayer online games to peer-to-peer applications. A computer program that runs within a distributed system is called a distributed program, and ''distributed programming'' is the process of writing such programs. There are many different types of implementations for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object-oriented Programming
Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of procedures (often known as ''methods''). A common feature of objects is that procedures (or methods) are attached to them and can access and modify the object's data fields. In this brand of OOP, there is usually a special name such as or used to refer to the current object. In OOP, computer programs are designed by making them out of objects that interact with one another. OOP languages are diverse, but the most popular ones are class-based, meaning that objects are instances of classes, which also determine their types. Many of the most widely used programming languages (such as C++, Java, Python, etc.) are multi-paradigm and they support object-oriented programming to a greater or lesser degree, typically in combination with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java (programming Language)
Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers ''write once, run anywhere'' ( WORA), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. , Java was one of the most popular programming languages in use according to GitHub, particularly for client–server web applications, with a reported 9 million developers. Java was originally develo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interface Description Language
interface description language or interface definition language (IDL), is a generic term for a language that lets a program or object written in one language communicate with another program written in an unknown language. IDLs describe an interface in a language-independent way, enabling communication between software components that do not share one language, for example, between those written in C++ and those written in Java. IDLs are commonly used in remote procedure call software. In these cases the machines at either end of the ''link'' may be using different operating systems and computer languages. IDLs offer a bridge between the two different systems. Software systems based on IDLs include Sun's ONC RPC, The Open Group's Distributed Computing Environment, IBM's System Object Model, the Object Management Group's CORBA (which implements OMG IDL, an IDL based on DCE/RPC) and Data Distribution Service, Mozilla's XPCOM, Microsoft's Microsoft RPC (which evolved int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unmarshalling
In computer science, marshalling or marshaling ( US spelling) is the process of transforming the memory representation of an object into a data format suitable for storage or transmission. It is typically used when data must be moved between different parts of a computer program or from one program to another. Marshalling can be somewhat similar or synonymous to serialization. Marshalling is describing an intent or process to transfer some object from a client to server, intent is to have the same object that is present in one running program, to be present in another running program, i.e. object on a client to be transferred to and present on the server. Serialization does not necessarily have this intent since it is only concerned about transforming data into a, for example, stream of bytes. One could say that marshalling might be done in some other way from serialization, but some form of serialization is usually used. It simplifies complex communications, because it uses ''co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class Skeleton
Skeleton programming is a style of computer programming based on simple high-level program structures and so called dummy code. Program skeletons resemble pseudocode, but allow parsing, compilation and testing of the code. Dummy code is inserted in a program skeleton to simulate processing and avoid compilation error messages. It may involve empty function declarations, or functions that return a correct result only for a simple test case where the expected response of the code is known. Skeleton programming facilitates a top-down design approach, where a partially functional system with complete high-level structures is designed and coded, and this system is then progressively expanded to fulfill the requirements of the project. Program skeletons are also sometimes used for high-level descriptions of algorithms. A program skeleton may also be utilized as a template that reflects syntax and structures commonly used in a wide class of problems. Skeleton programs are utilized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, printing, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer from cellular phones and video game consoles to web servers and supercomputers. The dominant general-purpose personal computer operating system is Microsoft Windows with a market share of aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marshalling (computer Science)
In computer science, marshalling or marshaling ( US spelling) is the process of transforming the memory representation of an object into a data format suitable for storage or transmission. It is typically used when data must be moved between different parts of a computer program or from one program to another. Marshalling can be somewhat similar or synonymous to serialization. Marshalling is describing an intent or process to transfer some object from a client to server, intent is to have the same object that is present in one running program, to be present in another running program, i.e. object on a client to be transferred to and present on the server. Serialization does not necessarily have this intent since it is only concerned about transforming data into a, for example, stream of bytes. One could say that marshalling might be done in some other way from serialization, but some form of serialization is usually used. It simplifies complex communications, because it uses ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class Stub
In a distributed computing environment, distributed object communication realizes communication between distributed objects. The main role is to allow objects to access data and invoke methods on remote objects (objects residing in non-local memory space). Invoking a method on a remote object is known as remote method invocation (RMI) or remote invocation, and is the object-oriented programming analog of a remote procedure call (RPC). Class stubs and skeletons The widely used approach on how to implement the communication channel is realized by using stubs and skeletons. They are generated objects whose structure and behavior depends on chosen communication protocol, but in general provide additional functionality that ensures reliable communication over the network. In RMI, a stub (which is the bit on the client) is defined by the programmer as an interface. The rmic (rmi compiler) uses this to create the class stub. The stub performs type checking. The skeleton is defined in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stub (distributed Computing)
{{unreferenced, date=June 2008 A stub in distributed computing is a piece of code that converts parameters passed between client and server during a remote procedure call ( RPC). The main idea of an RPC is to allow a local computer (client) to remotely call procedures on a different computer (server). The client and server use different address spaces, so parameters used in a function (procedure) call have to be converted, otherwise the values of those parameters could not be used, because pointers to parameters in one computer's memory would point to different data on the other computer. The client and server may also use different data representations, even for simple parameters (e.g., big-endian versus little-endian for integers). Stubs perform the conversion of the parameters, so a remote procedure call looks like a local function call for the remote computer. Stub libraries must be installed on both the client and server side. A client stub (sometimes called proxy) is responsi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Idempotent
Idempotence (, ) is the property of certain operations in mathematics and computer science whereby they can be applied multiple times without changing the result beyond the initial application. The concept of idempotence arises in a number of places in abstract algebra (in particular, in the theory of projectors and closure operators) and functional programming (in which it is connected to the property of referential transparency). The term was introduced by American mathematician Benjamin Peirce in 1870 in the context of elements of algebras that remain invariant when raised to a positive integer power, and literally means "(the quality of having) the same power", from + '' potence'' (same + power). Definition An element x of a set S equipped with a binary operator \cdot is said to be ''idempotent'' under \cdot if : . The ''binary operation'' \cdot is said to be ''idempotent'' if : . Examples * In the monoid (\mathbb, \times) of the natural numbers with multiplication, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XMLHttpRequest
XMLHttpRequest (XHR) is an API in the form of an object whose methods transfer data between a web browser and a web server. The object is provided by the browser's JavaScript environment. Particularly, retrieval of data from XHR for the purpose of continually modifying a loaded web page is the underlying concept of Ajax design. Despite the name, XHR can be used with protocols other than HTTP and data can be in the form of not only XML, but also JSON, HTML or plain text. WHATWG maintains an XHR standard as a living document. Ongoing work at the W3C to create a stable specification is based on snapshots of the WHATWG standard. History The concept behind the ''XMLHttpRequest'' object was originally created by the developers of Outlook Web Access (by Microsoft) for Microsoft Exchange Server 2000. An interface called ''IXMLHTTPRequest'' was developed and implemented into the second version of the MSXML library using this concept. The second version of the MSXML library wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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